The Changing Epidemiology of Invasive Fungal Infections

Abstract

Invasive fungal infections (IFI) are an emerging problem worldwide with invasive candidiasis and candidemia responsible for the majority of cases. This is predominantly driven by the widespread adoption of aggressive immunosuppressive therapy among certain patient populations (e.g., chemotherapy, transplants) and the increasing use of invasive devices such as central venous catheters (CVCs). The use of new immune modifying drugs has also opened up an entirely new spectrum of patients at risk of IFIs. While the epidemiology of candida infections has changed in the last decade, with a gradual shift from C. albicans to non-albicans candida (NAC) strains which may be less susceptible to azoles, these changes vary between hospitals and regions depending on the type of population risk factors and antifungal use. In certain parts of the world, the incidence of IFI is strongly linked to the prevalence of other disease conditions and the ecological niche for the organism; for instance cryptococcal and pneumocystis infections are particularly common in areas with a high prevalence of HIV disease. Poorly controlled diabetes is a major risk factor for invasive mould infections. Environmental factors and trauma also play a unique role in the epidemiology of mould infections, with well-described hospital outbreaks linked to the use of contaminated instruments and devices. Blastomycosis is associated with occupational exposure (e.g., forest rangers) and recreational activities (e.g., camping and fishing).The true burden of IFI is probably an underestimate because of the absence of reliable diagnostics and lack of universal application. For example, the sensitivity of most blood culture systems for detecting candida is typically 50 %. The advent of new technology including molecular techniques such as 18S ribosomal RNA PCR and genome sequencing is leading to an improved understanding of the epidemiology of the less common mould and dimorphic fungal infections. Molecular techniques are also providing a platform for improved diagnosis and management of IFI.Many factors affect mortality in IFI, not least the underlying medical condition, choice of therapy, and the ability to achieve early source control. For instance, mortality due to pneumocystis pneumonia in HIV-seronegative individuals is now higher than in seropositive patients. Of significant concern is the progressive increase in resistance to azoles and echinocandins among candida isolates, which appears to worsen the already significant mortality associated with invasive candidiasis. Mortality with mould infections approaches 50 % in most studies and varies depending on the site, underlying disease and the use of antifungal agents such as echinocandins and voriconazole. Nevertheless, mortality for most IFIs has generally fallen with advances in medical technology, improved care of CVCs, improved diagnostics, and more effective preemptive therapy and prophylaxis.

Scedosporium apiospermum brain abscesses in a patient after near-drowning – a case report with 10-year follow-up and a review of the literature

“…Both species are found worldwide in sewage, manure, polluted waters, indoor plant pots and greenhouses. Clinical manifestations show a great variety from cutaneous to disseminated diseases [3], [4], [5]. In the literature, many cases of Scedosporium apiospermum infections in immunocompromised patients [6], [7], [8], in transplanted patients [9], children [10] and other manifestations have been described [11], [12], [13], [14].…”

Candidaemia in a tertiary care academic hospital in Italy. The impact of C. parapsilosis complex on the species distribution and antifungal susceptibility

“…However, the widespread use of antifungal agents in the prophylaxis or empirical treatment of invasive mycoses has led to changes in the epidemiology and susceptibility of these yeasts [8,9]. In fact, recent studies highlighted the emergence of strains that are resistant to azoles and echinocandins [10], which might represent a major challenge for prophylactic and therapeutic approaches. Therefore, continuous surveillance studies at the local level are mandatory.…”

Methionine is required for cAMP‐PKA‐mediated morphogenesis and virulence of Candida albicans

“…The human fungal pathogen Candida albicans causes the most common fungal disease among hospitalized patients in the developed world (Enoch et al, 2017). Furthermore, it is the fourth-most common organism isolated in bloodstream infections (Wisplinghoff et al, 2004).…”